Manual and automatic control apparatus for combustion engines



Dec. 25, 1951 A. E. BAAK MANUAL AND AUTOMATIC CONTROL APPARATUS FORCOMBUSTION ENGINES 4 Sheets-Sheet 1 Filed April 21, 1943 .S'UPEECHAEGEEAFTER 60045,?

//Y7AKE MqsrE 647E Enventor fllber'i E Baa/Z Qttorneg Dec. 25, 1951 BAAK2,579,643

MANUAL AND AUTOMATIC CONTROL APPARATUS FOR COMBUSTION ENGINES FiledApril 21, 1945 4 Sheets-Sheet 3 ISnventor Alberi E Baak Gttorneg Dec.25, 1951 A E. BAAK 2,579,643

MANUAL AND AUTOMATIC CONTROL APPARATUS FOR COMBUSTION ENGINES FiledApril 21, 1945 4 Sheets-Sheet 4 iii Zhwentor Gttorneg Patented Dec. 25,1951 MANUAL AND AUTOMATIC CONTROL AP- PARATUS FOR COMBUSTION ENGINESAlbert E. Bank, Los Angeles, Calif., assignor to Minneapolis-HoneywellRegulator Company, Minneapolis, Minn., a corporation of DelawareApplication April 21, 1943, Serial No. 483,901

14 Claims. 1

The present invention relates to control apparatus, and particularly toapparatus wherein a control device is operated either automatically inresponse to the changes in a variable condition or by a manual control.

In many cases where a device is normally automatically controlled, itmay be desired under certain conditions, as for example in case of powerfailure, to control the device manually. This manual operation of thenormally automatically controlled device may be desirable because ofconsiderations of safety or convenience, or for other reasons.

In the following specification, I have illustrated my invention asapplied to a system for control-, ling the position of a throttle of aninternal com bustion engine. My invention has particular utility in sucha system, but it should be understood that its utility is not limited tothe specific system in which it is disclosed.

An object of my invention is to provide an improved control system, inwhich a control device is normally positioned in accordance with thevariations of a variable condition, and in which means are provided formanually positioning the device.

Another object of my invention is to provide an improved electricalcontrol system in which a device is normally automatically controlled byan electrical motor, and in which control of the device is transferredfrom the motor to a manually operable controller whenever for any reasonthe supply of power to the motor is discontinued. A further object is toprovide, in such a system, means whereby the control of the device istaken away from the manual lever. and restored to the motor upon thereturn of the power supply to the motor.

Another object of my invention is to provide an improved control systemin which a control device is normally automatically positioned so as tomaintain a variable condition at a predetermined value, but in which thedevice may be controlled under certain conditions by a manually operablelever, and in which means is provided whereby the same manually operablelever may be used during automatic control to establish the value of thevariable condition which is maintained by the control system.

A further object of my invention is to provide an improved system forcontrolling the pressure in the intake manifold of an internalcombustion engine, including power means normally effective to positionthe throttle, and means operative upon the discontinuance of the powersupply to said power means for placing the throttle under manualcontrol.

Other objects and advantages of my invention will become apparent from aconsideration of the appended specification, claims and drawings inwhich Figure 1 is a somewhat diagrammatic illustration of an internalcombustion engine of a type generally used on aircraft, together withthe air induction and exhaust systems associated with that engine.

Figure 2 is a somewhat diagrammatic illustration of an electricalcontrol system for the throttle and the super-charger in the system ofFigure 1, whereby the pressure in the intake manifold of the engine maybe automatically controlled, in which there is shown in some detail anarrangement by which the throttle may be manually positioned.

Figure 3 shows, in sectional elevation, a velocity and accelerationresponsive control device used in the system of Figure 2,

Figure 3A shows certain details of gearing for the apparatus of Figure3,

Figure 4 illustrates a detail of the device shown in Figure 3,

Figure 5 illustrates a modification oi the means for shifting thethrottle from automatic to manual control, which is applicable to thesystem of Figure 2,

Figure 6 illustrates a different type of mechanism for shifting thethrottle from automatic to manual control,

Figure 7 illustrates an automatically controlled latch which may besubstituted for the manually controlled latch of Figure 6 and Figure 8illustrates still another modification of the arrangement shown inFigure 2 for shifting the throttle from manual to automatic control.

Referring to Figure 1, there is schematically shown an internalcombustion engine In of a type generally used in aircraft. The air forsupporting combustion in the engine It) passes from an intake ll througha turbo-compressor I2, a conduit I 3, an after-cooler M, a conduit [5, acarburetor IS in which a throttle valve I1 is located. an engine drivencompressor 22, and an intake manifold 20 to the engine Hi.

The exhaust gases from the engine pass through an exhaust manifold 25and a turbine 21. A waste gate or valve 3| is provided, by means ofwhich gases may be bled from the exhaust manifold 25 and permitted topass directly to the outside air without passing through the turbine 21.

The turbo-compressor I2 is driven by the turbine 21 through a shaft 32.

The after-cooler I4 is provided to reduce the temperature of the airleaving the turbo-compressor I2, wherein the temperature is increaseddue to the heat of compression. In the aftercooler, the compressed airreceived from the turbo-compressor I2 is passed in heat exchangerelation with cooling air received from an intake 33, which isdischarged to the atmosphere after passing through the after-cooler.

FIGURE 2 Referring to Figure 2, it may be seen that the waste gate 3| isdriven by a motor 200 through a gear train MI. The motor 200 is of thesplit phase type, being provided with a pair of field windings 202 and203, which are spaced 90 electrical degrees apart, and an armature 204.The field winding 203 is supplied with electrical energy from asecondary winding 205 of a transformer 205. The energizing circuit forwinding 203 may be traced from the upper terminal of secondary winding205 through a condenser 208, motor field winding 203, and a conductor2H3 to the lower terminal of secondary winding 25.

The fiow of electrical energy to the field winding 202 is controlled byan amplifier 2 I l, which is connected to the winding 202 through a pairof conductors 2I2 and 2I3. The amplifier MI is supplied with electricalenergy from another secondary winding 2| 4 of transformer 206. Theamplifier 2 I I is connected to the secondary winding 2 I4 through apair of conductors 2| 5 and 2 I6.

The amplifier 2II is provided with a pair of signal input terminals 220and 22I, and operates to supply the motor field winding 202 withalternating current of a phase dependent upon the phase of analternating signal potential impressed upon the input terminals 220 and22I. Any suitable amplifier having such a characteristic may be used,but I prefer to use one of the type shown in Figure 1 of the co-pendingapplication of Albert P. Upton, Serial No. 437,561, filed April 3, 1942,now Patent No. 2,423,534, dated July 8, 1947.

As stated above, the link I9 has one end connected to the throttle I! bythe lever arm 40 which is in turn directly connected to the throttlevalve IT. The other end of the link I9 is pivotally attached to a plate4| which is mounted to freely rotate on a shaft 42. The shaft 42 may bedrivingly connected to the plate M by means of a planetary gearmechanism generally indicated at 43. This planetary gear mechanismincludes a sun gear 44 fixed on the shaft 42, a plurality of planetgears 45 carried by stub shafts mounted on the plate 4|, and a ring gear40 which is concentric with the sun gear 44 and engages the planet gears45. The ring gear 46 may be supported by any suitable means (not shown),which maintains it in engagement with the planet gears 45. The outersurface of the ring gear 46 is smooth, and forms a drum which cooperateswith a, brake shoe 41. The brake shoe 41 is connected to the armature I0of an electromagnet 48. The armature I0 is biased to the left by aspring II. When the electromagnet 43 is energized, the armature I0 ismovedhto the right against the force of spring II, so that the brakeshoe 41 is held in engagement with the drum surface of the ring gear 43,thereby holding the gear 40 locked against rotation. When the ring gear46 is thus locked, a driving reiation'is established between shaft 42and the plate 4|, as will be readily understood by those familiar withconventional planetary gearing arrangements. The shaft 42 is driven by amotor I00 through agear train IOI The motor I00 is of the same generaltype as motor 200, being provided with a pair of field windings I02 andI03, spaced electrical degrees apart and an armature I04. The fieldwinding I03 is supplied with electrical energy from a transformersecondary winding I05. The energizing circuit for winding I03 may betraced from the upper terminal of secondary winding I 05 through acondenser I03, field winding I03 and a conductor II 0 to the lowerterminal of secondary winding I05.

The fiow of electrical energy to field winding I02 is controlled by anamplifier III, which is connected to the field winding I02 through apair of conductors H2 and H3. The amplifier III is supplied withelectrical energy from another transformer secondary winding II4. Theamplifier I I i is connected to the secondary winding II 0 through apair of conductors H5 and H6.

The amplifier I i I is provided with a pair of signal input terminalsE20 and I25, and operates to supply the motor field winding 02 with analternating current of a phase dependent upon the phase of analternating signal potential impressed upon the input terminals l2 andI2I. The amplifier Ill may be of the same type as amplifier 2| I.

The plate 4| is provided with an arcuate surface concentric with theshaft 42, and notched,

. as at 50, to receive the armature 5| of an electromagnet 52. Theelectromagnet 52 is mounted on an arm 53, which is freely rotatable onthe shaft 42. A link 54 is pivotally attached to the upper end of arm 53and the other end of link 54 is pivotally attached to a manuallyoperable control lever 55 which rotates about a fixed pivot 50. The freeend of the lever 55 moves adjacent a stationary scale 51.

The electromagnets 43 and 52 are connected in parallel to the terminalsof a secondary winding 60 of a transformer GI having a primary winding62 connected to supply lines 63 and 64.

The transformer 206 for the waste gate motor has a primary winding 65,which is also connected to supply lines 03 and 64. A switch 66 connectsthe supply line 54 with a line 61 extending to the source of electricalenergy for the system. The transformer secondary windings I05 and H4 mayalso be located on the transformer 200, or on another transformer whoseprimary winding is connected to the lines 63 and 64.

Considering the motor 200, it will be seen that the phase pf the currentflowing in winding 203 is fixed with respect to the phase of the voltagesupplied to lines 63 and 64 by the source of energy. From the well knowncharacteristics of split phase motors, it will be understood that if thefield winding 202 is supplied with alternating current which leads thecurrent supply to winding 203 by 90 electrical degrees, the motor 200rotates in one direction, while if the field winding 282 is suppliedwith current which lags the current in winding 283 by 90 degrees, themotor 288 runs in the opposite direction. Similarly, the direction ofrotation of motor I88 depends upon the phase of the current supplied towinding I82 with respect to the fixed phase of the current supplied towinding I 83.

The alternating signal potentials applied to the input terminals 228 and221 of amplfier 2H and to the input terminals I28 and HI oi amplifier Hiare determined by the electrical conditions existing in a compoundnetwork, which consists of three electrical networks connected inseries. The circuit between the amplifier input terminals 228 and 221may be traced from terminal 228 through a conductor 222, a firstelectrical network 223, a conductor 224, a second electrical network225, a conductor 228, a third electrical network 221, and a conductor228 to amplifier input terminal 22l.

A similar electrical circuit may be traced from amplifier input terminalI28 through a conductor 122, the first network 223, conductor 224, thesecond network 225, the conductor 228, the third network 221, andconductor 228 to amplifier input terminal I2l. 1

The network 221 includes a transformer secondary winding 238, across theterminals of which is connected a slidewire resistance 23!, by means ofconductors 232 and 233. The conductor 228 is connected to a slider 234which cooperates with resistance 23L The slider 234 is mounted on theend of arm 53, and is movable along the resistance 23l by manipulationof the manually operable lever 55. The slider 234 and the resistance 23!together form a control point adjuster 238 for the control system.

Another slide wire resistance 229 has one of its terminals connected bya conductor 248 to the left terminal of secondary winding 238, and theopposite terminal of resistance 229 is connected by a conductor 249 to acenter tap on secondary winding 238. A slider 2|8 cooperates with theresistance 229, and is manually adjustable with respect to that slidewire. Slider 2 l8 and the resistance 229 together form a calibratingpotentiometer 2 I 9.

the center of resistance 23! by a conductor 2I1.

The conductor 2|1 is provided to decrease the impedance of the networkbetween slider 234 and slider 2 l8, and does not otherwise affect theoperation of the system.

The electrical network 225 includes a secondary winding 231, acrosswhose terminals a slidewire resistance 238 i connected by means ofconductors 248 and 2. A slider 242 cooperates with resistance 238, andis connected to conductor 228. The resistance 238, the slider 242, andthe operating mechanism therefor together form a primary pressurecontroller 243.

The pressure controller 243, which is shown diagrammatically in Figure1, operates to move the slider 242 along the resistance 238 inaccordance with the absolute pressure existing within the intakemanifold 28. The pressure controller 243 includes a bellows 245, theinterior of which is connected through a pressure take-off duct 244 to apoint within the intake manifold, the pressure in which is to becontrolled by this system. A second bellows 248 in the controller 243 isevacuated, so that its expansion and contraction depends only uponatmospheric pressure. The two bellows 245 and 248 are mounted with theirfree ends extending toward each other, and

, 6 those free-ends are connected by a link 241. An intermediate pointon the link 241 is connected, as by a pin and slot connection, with theslider 242. The slider 242 is mounted for pivotal movement about itsupper end.

As stated above, the interior of bellows 248 is evacuated, and itsexterior is exposed to atmospheric pressure, so that it exerts a forcetending to move the link 241 to the left, whose magnitude is dependentupon the atmospheric pressure. Since the exterior of bellows 245 is alsoexposed to atmospheric pressure, that pressure exerts a force tending tocollapse the bellows 248 and to move the link 241 to the right, therebyopposing and cancelling the force exerted by bellows 248 tending to movelink 241 to the left. Since the interior of bellows 245 is exposed tothe pressure to be controlled, it may be seen that this pressure exertsa force acting on the link 241 towards the left, and that this force isopposed only by the resilience of the bellows 248 and 248. Therefore,the position of slider 242 with respect to resistance 238 is a measureof the absolute pressure within the intake manifold 28.

A second slidewire resistance 258 is also connected across the terminalsof secondary winding 231, through conductors 25I and 252. A slider 253cooperates with the resistance 258 and is connected to conductor 224.The resistance 258 and t-- slider 253 together form an accelerationcompensating controller 254. The controller 254 is operated inaccordance with the acceleration of the turbine shaft 32 by anacceleration responsive control device schematically indicated at 255. Asuitable acceleration responsive control device 255 is described indetail in Figure 3. For the present purposes, it may be stated that theslider 253 is maintained in the position shown in the drawing as long asthe turbine shaft 32 (see Fig. 1) rotates at a constant speed. Uponacceleration of the shaft 32, the slider 253 is moved to the right alongresistance 258. A contact 282 provides a "dead spot" at the left end ofthe resistance 258, so that small accelerations of the turbine 21 haveno eifect on the control system.

The network 223 includes a transformer secondary winding 288. Aslidewire resistance 28! is connected by a conductor 282 to one terminalof secondary winding 288 and by a conductor 283 to a tap 283 at anintermediate point on secondary winding 288. A slider 284 cooperateswith resistance 28l and is connected to conductor 224. The slider 284and resistance 28! together form a velocity responsivecompensatingcontroller 285, which is operated by a velocity responsive controldevice schematically indicated at 288. The cletails of the velocityresponsive control device 285 are shown in detail in Figures 3 and 4.

The network 223 also includes a waste gate follow-up potentiometer 213and a throttle follow-up potentiometer 238. The waste gate follow-uppotentiometer 213 includes a slidewire resistance 281 and a slider 212cooperating therewith. The slider 212 is connected to conductor 222, andis moved along the resistance 281 by the motor 288 acting through thegear train 28l, concurrently with the operation of the waste gate 3 i.The left terminal oiresistance 281 is connected through a, conductor 288and a conductor 289 to an intermediate tap 284 on secondary winding 288.The right terminal of resistance 281 is connected through a conductor21! to. the right terminal of secondary winding 288.

The left terminal of resistance 23l is connected through a conductor 233to a tap 294 on sec- 7 ondary winding 260 locatedbetween the taps 283and 284. The right terminal of resistance 29 I is connected through aconductor 295 and conductor 269 to tap 284. The slider 292 is fixed onthe plate 4! and therefore moves across the resistance 29I concurrentlywith the movement of the throttle I1.

All the secondary windings 230, 231 and 260 are on the same transformer,which may be the transformer 206, or another transformer whose primarywinding is connected to the same supply lines 63 and 64 as the primarywinding 65 of transformer 206. Therefore, the alternating potentials atthe terminals of these three transformer windings are in phase with eachother. The signal potentials impressed on the input terminals of theamplifiers III and 2I I are therefore the algebraic sums of a number ofpotentials produced in the networks 223, 225 and 221.

Operation of Figures 1 and 2 For the sake of convenience in consideringthe operation of this system, let us consider only the potentialconditions existing during a half cycle when the terminals of thetransformer windings have the polarities indicated by the legends in thedrawings. In other words, the left terminals of windings 231 and 260 areconsidered as positive, and the right terminal of secondary winding 230is considered as positive. In order to have a reference potential, theconductor 228 may be considered as being grounded, as indicated at 285.If the potential conditions in the circuit are thus considered duringone-half cycle, it will be understood that the potential conditionsduring the opposite half-cycle are opposite. The consideration of thepotential conditions during only onehalf cycle merely forms a convenientway of considering the phase relationships of the alternating potentialswhich actually exist in the system.

Considering first the network 221, it may be seen that when the slider234 is at the position shown in the drawing, its potential is the sameas that of the center tap on secondary winding 230. At the same time,the slider 2I8 is at an intermediate point along the resistance 229 andhence its potential is negative with respect to the center tap onwinding 230. It may therefore be seen that the network 221 introducesinto the series circuit connecting the amplifier input terminals apotential of a polarity such that slider 2I8 and conductor 226 are madenegative with respect to the grounded conductor 228.

Considering next the network 225, it will be seen that when the sliders242 and 253 are in the positions shown in the drawing, the network 225introduces into the series circuit a potential whose magnitude dependsupon the potential of slider 242 with respect to the left terminal ofsecondary winding 231. This potential is of a polarity such that slider253 is positive with respect to slider 242. The potential of slider 253with respect to ground depends upon the relative magnitude of theopposing potentials introduced by the networks 221 and 225. For thepurposes of the present discussion, it may be assumed that the potentialintroduced by network 225 is larger than that introduced by network 221,and hence that slider 253 is positive with respect to ground.

Considering now the network 223, it may be seen that since the slider264 is at the extreme right end of its associated resistance 26I, theconductor 263 is at the same positive potential with respect to groundas slider 258. The resistance 29I of the throttle follow-uppotentiometer 290 and the resistance 261 of the waste gate follow-uppotentiometer 213 are both connected to the secondary winding 260 insuch a manner that their left terminals are positive with respect totheir right terminals. Also, the right terminal of resistance 29I is inthe same potential as theleft terminal of resistance 261. When theslider 292 of the throttle follow-up potentiometer is at the positionshown in the drawing, at the center of resistance 29 I, the potential ofthe slider 282 is equal to the potential of a point on the secondarywinding 260 half way between the taps 294 and 284. This point on thewinding 260 is negative with respect to tap 283 which, as was justshown, is positive with respect to ground.

It may be assumed that the potential difference between tap 283 and theslider 292 is exactly equal and opposite in polarity to the positivepotential of tap 283 with respect to'ground. Therefore the slider 292 isat ground potential. Since the slider 292 is connected through conductorI22 to input terminal I20 of amplifier III, it may be seen that inputterminal I20 is at ground potential. Since input terminal |2I isgrounded through conductor 228 and ground connection.

285, no potential difference exists between the input terminals ofamplifier III. Therefore, the winding I02 of motor I00 is not energized,and the motor does not operate. The throttle I1 remains in the positionshown in the drawing. The left terminal of resistance 261, and hence theslider 212, is at a potential more negative than that of slider 292.Since the slider 292 is at ground potential, the slider 212 is negativewith respect to ground and hence the input terminal 220 of amplifier 2IIis negative with respect to ground. It may be assumed that theconnections of amplifier H I are such that when the input terminal 220is negative with respect to ground, that the winding 202 of motor 200 isenergized with current of a phase which causes rotation of the motor 200in a direction to open the waste gate 3 I. Since the waste gate 3|is'already wide open, it is in engagement with a suitable stop structure(not shown), and hence the moto 200 is stalled. As mentioned above, theconnections of amplifier 2II are so arranged that when the inputterminal 220 is negative with respect to conduit terminal 22I, the motor200 is caused to operate in a direction to open the waste gate. When theinput terminal 220 is positive with respect to grounded terminal 22I,the motor 200 is operated in a. direction to close the waste gate.Similarly, the connections of amplifier III are such that when inputterminal I 20 is negative with respect to ground, the motor I00 isoperated in a direction to close the throttle I1. When the inputterminal I20 is positive with respect to grounded terminal I2I, themotor I00 is operated in a direction to open the throttle I1. It may bestated that both the throttle motor I00 and the waste gate motor200 areoperated in a direction of increasing safety when the ungroundedterminals of their associated amplifiers are made negative with respectto ground, and that these motors operate their respective load devicesin a direction of increasing activity when the ungrounded terminals oftheir associated amplifiers are positive with respectto ground.

It should be noted that'the position of the slider 292 adjacentresistance 29I has no effect on the control potential applied toterminals 220 and 22I of amplifier 2I I associated with the waste gate.Similarly, the position of slider 212 with respect to resistance 26'!has no eifect on the control potential impressed between input terminalsI20 and I2I of the throttle amplifier III. There remains to beconsidered the controlling effect on both the waste gate and thethrottle of changes in the position of the primary pressure controller223, the acceleration responsive controller 255, the velocity responsivecontroller 256, the control point adjuster 230, and the calibratingpotentiometer 2 I9.

As the potential of the conductor 224 connecting networks 225 and 223increases in a positive sense due to an operation of one of thepotentiometers in the networks 221 and 225. it may be seen that thepotential of slider 264. conductor 263 and tap 283 likewise become morepositive with respect to ground. This positive potential is transmittedthrough the network 223 to the slider 292, conductor I22 and amplifierinput terminal I20. As previously stated, a potential of this polarityapplied to input terminal I20 causes the motor I to drive the throttleII in an opening direction. At the same time, the slider 292 is moved tothe right along resistance 29I, thereby reducing the positive potentialapplied to amplifier input terminal I20. As soon as this positivepotential is reduced to zero, the motor I00 stops, and the system isagain balanced with the throttle in a new position. If the positivepotential at the tap 283 continues to increase, the throttle I!eventually reaches its fully open position, at which time the slider 292is at the extreme right terminal of resistance 29I. If the potential attap 283 still continues to increase in a positive sense, the potentialof slider 212 and hence of amplifier input terminal 220. also becomespositive with respect to ground. As previously stated, this causes themotor 200 to rotate in a direction to close the waste gate, and tooperate the slider 212 to the right along resistance 213 to restore theinput terminal 220 to ground potential. At this time, an additionalpositive potential is applied to input terminal I20 of amplifier I I I,but the motor I00 is then stalled, since the throttle I1 is already inits fully open position.

It may therefore be seen that, as the potential at the conductor 224increases positively with respect to ground, the system operates firstto open the throttle and after the throttle is fully open to close thewaste gate.

Considering now the effect of the operation of the primary pressurecontroller 243 on the system, it may be seen that as the pressuresupplied from the intake manifold 20 through the duct 244 to the bellows245 increases, the slider 242 is moved to the left along resistance 238and the conductor 224 is thereby made less positive with respect toground. On the other hand a decrease in the pressure within the bellows245 causes the slider to move to the right along resistance 238, therebymaking the conductor 224 more positive with respect to ground. Thus itmay be seen that an increase in the controlling pressure causes thewaste gate to be opened and, after the waste gate is fully opened, thethrottle is moved toward its closed position. The operation of the wastegate toward its open position has a decreasing effect on the controllingpressure, and likewise the movement of the throttle toward closedposition has a decreasing effect on the controlling pressure. Hence thesystem responds to an increase in the controlling pressure by causing apressure All decrease tending to restore it to its previous value.Likewise the system responds to a decrease in the controlling pressureby causing a suitable operation or the throttle or the waste gate toagain increase the pressure and restore it to its desired value.

In a similar manner, it may be seen that a movement of the slider 253 tothe right by the acceleration responsive controller 255 causes a morenegative potential to be impressed on the input terminals I20 and 220,and hence causes an operation of-the throttle or the waste gate in apressure decreasing direction. The purpose of the accelerationresponsive controller 255 is to anticipate changes in the pressure atthe intake manifold 20 which are caused by acceleration of theturbine-driven supercharger. Due to the inherent lag in the system, theincreased pressure Wlil not be observed at the intake manifold untilsome time after the acceleration of the turbine and supercharger hastaken place. Hence, if the controller 255 were not provided, thepressure controller 243 might continue to call for increased speed ofthe supercharger at a time when the supercharger was already moving fastenough to supply the required pressure to the intake maniiold aftersteady pressure conditions had become established. This would cause thecontrol system to overshoot with the result that the pressure beingcontrolled would hunt or oscillate about the desired value which thesystem was supposed to maintain. By utilizing the accelerationresponsive controller 255, the system anticipates the increase inpressure which will result from the increased speed of the turbine, andthe waste gate is thereby slowed .down before the pressure has reachedthe desired value and finally stopped at a position where the pressureis maintained exactly at that value.

When the slider 264 is moved to the left from the position shown in thedrawing, the potential of the input terminals I20 and 220 of thethrottle and waste gate amplifiers are made increasingly negative, andhence a motion of the waste gate in a pressure decreasing direction iscaused. The

controller 266 operates as a limit controller to prevent the turbine andsupercharger from operating at too high a speed. As explained in moredetail in connection with Figures 3 and 4, the velocity controller 266operates the slider 2E4 across resistance 26I as a time function ofvelocity. In this way, a resilient upper limit to the velocity of theturbine and supercharger is provided, which effectively limits the speedin which the turbine can rotate, but nevertheless at any given speed ofthe turbine permits an increase in speed it required.

If the slider 234 is moved to the right from the position shown in thedrawing, the potentials applied to the input terminals I20 and 220 aremade increasingly negative with respect to ground. T his causes apressure decreasing movement of the throttle or waste gate, and hence adecrease in the pressure within the bellows 245. The slider 242therefore assumes a new position along resistance 238 so that the systemis again balanced, but with a new and lower value of pressure in thecarburetor I6. Similarly, a movement of slider 234 to the left alongresistance 23I re sults in the establishment of an increased pressurevalue within the intake manifold. Hence, the movement of slider 234 issaid to adjust the control point of the system.

The calibrating potentiometer 2I9 is provided to make small adjustmentsin the output poten- 11 tial of network 221 in order that the positionof the lever 55 adjacent the scale 51 may accurately indicate thepressure value being maintained by the system in the intake manifold.

If, while the system of Figure 2 is operating to automatically controlthe pressure of the air supplied to the intake manifold, the powersupply should fail, the deenergization of the electromagnet 48 resultsin the movement of the core 10 to the left under the influence of thebiasing spring 1|, thereby disengaging the brake shoe 4'! from thesurface of the ring gear 46. At the same time, the sun gear 44 iseffectively locked, since the motor I is deenergized and its rotor I04is therefore stationary, and because the rotor |04 is very diflicult tomove from the low-speed end of the reduction gear train |0|.

At the same time, deenergization of electromagnet 52 allows the core 5|to drop into the notch 50, if the core 5| and the notch 50 happen to bealigned as indicated in the drawing. If the core 5| and the notch 50 arenot aligned when deenergization of the electromagnet 52 takes place, thecore 5| will engage the arcuate surface of the plate 4|. Then, by movingthe lever 55, theoperator can move the electromagnet 53 above the plate4| until the core 5| is aligned with the notch 50 whereupon the core 5|drops into the notch. After the core 55 engages the notch, the pilot ofthe aircraft can, by moving the lever 55, manually position the throttleH. The motion is transmitted from the lever 55 through the link 54, thearm 53, the electromagnet core 5f, the plate 4|, the link It and thelever arm 40, to throttle valve Hi. When the plate M is moved in thatmanner, the planet gears 45 rotate about the sun gear tit, the free ringgear 06 permitting such rotation.

It should therefore be apparent that I have provided a system whereinthe position of the throttle is normally automatically controlled inaccordance with the intake manifold pressure and other controllingconditions, but wherein upon the failure of the power supply to theautomatic control system, the throttle is mechanically connected to thesame lever which during automatic operation serves to adjust the controlpoint of the system. Furthermore, it will be apparent that by openingthe switch 66, the pilot of the aircraft can manually discontinue thesupply of power to the system at any time, so that he can place thethrottle under manual control at will. It should also be apparent thatupon restoration of power to the system, the throttle is l2 otherwiseadapted for an extension of the shaft 32 of turbine 21 (see Figure 1).The center portion of the base of easing carries a bearing 303 in whichthe shaft 302 is journaled. The casing 30| is provided with a cover 304carrying a bearing 305 in its central portion, in which bearing theupper end of the shaft 302 is journaled.

A mass 303, having a hollow, generally cylindrical form is rotatablymounted on the shaft 302 by means of a bearing 301. A cover 308 isattached to the upper surface of the mass 306 by means of screws 3|0,and is provided with a hearing 3 in which the shaft 302 is journaled. Acoil spring 3|2 has one end suitably attached to a collar 3|3 carried bythe shaft 302, and its other end is received in a suitable aperture inan extension of the cover 308. The mass 306 is thereby flexiblyconnected to the shaft 302. When the shaft 302 is rotating at a constantspeed, the angular position of the mass 306 with respect to the shaft302 does not change, but upon accelertion of the shaft 302 the mass 306changes its angular position with respect to the shaft 302 because ofits inertia. The spring 3|2 permits a limited amount of relativemovement of the shaft 302 and mass 306, and biases the mass 306 so thatit always returns to the same angular 7 position with respect to shaft302 after such a again placed under automatic control without attentionon the part of the operator. The return of power to the system resultsin the energization of. the electromagnets 48 and 52, therebydisconnecting the arm 53 from the plate 4| and looking the ring gear 46against rotation. The lever 55 is mechanically disconnected from thethrottle II when the core 5| is withdrawn from the notch 50, and themotor I00 is operatively connected to the throttle IVwhen the ring gear46 is locked.

FIGURES 3 AND 4 There is shown in Figure 3 a control device whichincludes an acceleration responsive controller which may be used as thecontroller 255 of Figure 2, and a velocity responsive controller whichmay be used as the controller 266 of Figure 2.

Referring to Figure 3, there is shown a housing 30l, having an aperturein the central portion of its base, through which aperture passes ashaft 302, the lower end of which is keyed or relative movement.

The outer periphery of the cover 306 is beveled, and is adapted tointerfittingly engage a similar beveled portion at the lower end of acylindrical cam member 3M. The cylindrical cam member 3M is held inplace against the cover 308 by means of an outer clamping ring 3 5 whichengages the outer surface of the beveled portion of cam member M4. Thering 3H5 may be clamped against the cover 308 by means of bolts 3|6.When so clamped, it holds the cam member 3 against rotation relative tothe mass 306. By loosening the bolts 3 6, the cam member 3| 4 may beadjusted to any desired angular position with respect to the mast 306.

The shaft 302 is slotted, asat 3 l. The portion of shaft 302 above theslot 3H is hollow. A pin 3|8 passes through the slot 3", and has itsopposite ends fixed in a collar 3|9, which is slidable along the shaft302. Because of the pin 3|8 and slot 3H, the collar 3|9 is not rotatablewith respect to shaft 302.

The collar 3|9 carries a spider comprising a plurality of arms 32l, eachof which has a bentup extremity, and in that extremity carries a I stubshaft 322, on which rotates a roller follower 323 for cooperation withthe cylindrical cam 3|4. In the structure shown in the drawing, thereare three arms 32| on the spider. The cam member 3|4 iscircumferentially divided into three similar cam portions, having agradual rise from the lowest point thereon to a high point thereon. Atthe high point of the cam, the cam surface suddenly rises, terminatingin vertical portion, thereby limiting the angular movement of the camwith respect to the followerassembly, which includes the spider arms 32|and the followers 323. A collar 324 is fixed to the shaft 302 andcarries a plurality of outwardly extending arms 325, which are equal innumber to the spider arms 32L Each of the arms 325 has a bent-up portion326, which is received in an aperture in one of the arms 32L The purposeof the arms 325 and their extensions 325 is to guide the followerassembly and to prevent its rotation relative to the shaft 302. While Iprefer to use three operative connection with 13 similar cam portions,and three followers spaced at equal angles, because of balanceconsiderations, it should be understood that any suitable number of camportions and followers may be used.

Within the hollow portion of the shaft 302 above the pin 3i8, theremoves a thrust rod 321. The thrust rod 321 is tapered at both ends tofit into craters in the pin 3! and in a cross head 323, whose ends areslidably received in a pair of spaced plates 330 and 331, the latterbeing broken away in the drawing to illustrate the parts beneath it. Therod 321 is preferably of smaller diameter than'the passage through theshaft 302, so that it does not frictionally engage on the plates 330 and33I, as shown at 333. Only one leg of the U-shaped bracket 332 appearsin the drawing, but it is believed that its construction will be readilyapparent. A pin and slot connection 334 is provided so that the bracket332 may be angularly adjusted about the pivot 333. The ends of the armsof the U-shaped bracket member 332 carry a shaft 335. Pivotally mountedon the shaft 335 is a bracket 336, a portion of which extends into thepath of movement of the cross head 323. The right-hand portion of thebracket 336 terminates in a tongue 331. A tension spring 338 isstretched between the tongue 331 and another tongue 340 associated withthe plates 330 and 33i. The spring 333 biases the bracket 336 forcounter-clockwise rotation about the shaft 335, thereby maintaining thebracket 336 in engagement with the cross head 320.

The left end of bracket 336 carries an insulating plate 34l, on which ismounted a slider 342. The extremity of slider 342 cooperates with'aslidewire resistance 343, which is mounted on the cover 304 of thecasing 30l. The opposite ends of the slidewire 303 are connected throughconductors 344 and 345 to pins in a multiple plug electrical connectorcarried on a projection from plates 330 and 33 l. A cap 341 encloses theresistance 343 and its related elements. A pig tail connection 343connects the slider 342 to another of the pins in the multiple plugelectrical connector.

Operation of acceleration responsive controller The shaft 302 rotates ina counter-clockwise direction as viewed from the bottom in Figure 3.

When the shaft 302 is rotating at a constant velocity, the angularposition of the mass 306 relative to the shaft 302 is such that thefollowers 323 rest near the lower portions of the cam member 3| 4. Atthat time, the pin 3l0 is near the bottom of the slot 3", and the slider342 is near the lower end of the slidewire resistance 343.

Upon acceleration of the shaft 302, relative movement takes placebetween the mass 306 and the shaft 302, as previously explained. Sincethe cam 3| 4 is fixed to the mass 306, and since the followers 323 moveangularly with the shaft 302, the relative motion of the mass 306 andshaft 302 causes the followers 323 to be moved up the surfaces on thecam member 3, thereby moving the pin 3|8, the thrust rod 321, and theslider 342 upwardly. Movement of the slider 342 in an upward directionis equivalent to the movement of slider 263 of Figure 2 to the rightalong resist ance 263.

Velocity responsive controller A plate 360 is fixed on the shaft 302Just below the mass 303. The plate 360 is provided with diametricallyopposite pairs of downwardly extending ears 361. In each of the pairs ofears 35i is journaled a shaft on which is carried a weight 362. Anextension 363 of the weight 362 extends toward the shaft 302, so as toprovide a sort of bell-crank lever arrangement. The extensions 363 onthe weights 362 engage the upper surface of a housing 364 which isslidable on the shaft 302. A compression spring 366 is carried withinthe housing 364 and between the top of the housing and a nut 363, whichis threaded on a sleeve 361 fixed on the shaft 302. The sleeve 351 isflattened along one side, as indicated at 358. A washer 360 retains thespring 355 between the nut 366 and the housing 354. The aperture in thewasher 360 is shaped to conform with the sleeve 363, so that the washeris not rotatable on the sleeve. The washer 360 has a down struck lug 36lat one side thereof which engages 'one of the exterior surfaces of thenut 356 and prevents rotation of the latter.

When it is desired to adjust the tension in the spring 356, the washer360 may be forced upwardly, freeing the down struck lug 36l fromengagement with the nut, whereupon the nut 356 may be rotated on thesleeve 361. After the nut has been moved to its desired position, thewasher 360 may then be released, allowing the lug 36I to again engagenut 356 and lock it against rotation.

The lower portion of the housing 364 is attached to a plate 362, whichbears against a sleeve 353, nested within a cup-shaped member 363. Thesleeve 353 is preferably made of Bakelite, or other suitable wearresisting material. The cup-shaped member 363 is pivotally mounted on apair of stub shafts 363 (see Fig. 4), which are fixed at diametricallyopposite points 5 on the cup-shaped member 363, and. are jour- 7 theunder surface of spring member 313, which is self-biased into engagementwith bolt 331. It will be seen that by turning the bolt 331, the fulcrumpoint of the lever 364 may be moved upwardly or downwardly, therebyproviding an additional means for adjusting the speed of shaft 302 atwhich lever 364 is actuated to its controlling position, as explainedhereinafter.

The lever 364 extends from the pivot 365 across the casing 30I, spanningthe shaft 302 and carrying a button 366 adapted to bear against the endof a clutch shaft 361, which is biased upwardly into engagement with thebutton 366 by means of a compression spring 366.

A portion of the shaft 302 is cut for a pinion gear as at 310, and agear 31! mates with the pinion gear 310. The gear 31i is rotatablymounted on the clutch shaft 361. Through a suitable gearing connection,comprising gear 600, pinion 50l carried thereby and idler gear 602, asecond gear 312 also rotatably mounted on the 15 clutch shaft 361 isdriven in the opposite direction to the gear 31! and at a lower speed.It may be for example, that the gear 312 is driven at one-third thespeed of the gear 3. The clutch shaft 361 also carries a double facedclutch member 313, which is fixed on the said clutch shaft. Near itsupper end, the clutch shaft carries a gear 314, which is also fixedon'the clutch shaft, and which mates with a gear 315 fixed on a threadedshaft 316. An internally threaded nut 311 rides on the threaded shaft316, and is moved therealong upon rotation of the shaft 316. The nut 311carries a slider, not shown on the drawing, which engages the surface ofa slidewire resistance 310 mounted in back of the shaft 316. Anextension 380 at theend of lever 364 lies in the path of the nut 311 atthe lower end of its range of movement.

Operation of velocity responsive control device As long as the angularvelocity of the shaft 302 is below a predetermined value, determined bythe compressive force of spring 355, the clutch shaft 361 is biasedupwardly by the springs 368 so that clutch 313 engages gear 312. At sucha time, the clutch shaft 361 is rotated in a direction so that thethreaded shaft 316 rotates to carry the nut 311 downwardly. If therotative speed of the shaft 302 remains below the said predeterminedvalue for a suilicient length of time, the nut 311 moves downwardlyuntil it engages the extension 380 of the lever 364, whereupon -thelever 364 is moved downwardly, carrythat velocity is greater than apredetermined ing withit the clutch shaft 361 and causing disengagementof clutch 313 from the gear 312. Thereupon the clutch shaft 361 and thethreaded shaft 316 are no longer rotated, and the. slider carried by thenut 311 remains at the lower end of resistance 318.

If the angular velocity of the shaft 302 increases beyond the valuedetermined by the compression of the spring 35, the centrifugal forceacting on the weights 352 causes them to move outwardly, and theextensions 353 on the weights 352 move the housing 354 downwardly,thereby carrying the lever 364 downwardly. This further downwardmovement of lever 364 causes the clutch shaft 361 to be moveddownwardly, carrying the clutch 313 into engagement with gear 31l. Theclutch shaft 361 is thereupon rotated in such a direction that thethreaded shaft 318 rotates in a direction to move the nut 311 upwardly,thereby moving the slider carried by nut 311 upwardly along theresistance 318.

An upward movement of this slider along resistance 318 corresponds to amovement of slider 264 of Figure 2 to the left along resistance 26l.

It may therefore be seen that as long as the angular velocity of shaft302 remains below a predetermined value, the slider is maintained at thelower end of resistance 316. When it increases above that value, theslider is moved upwardly along the resistance 316. The position of theslider on the resistance 316 at any time is not determined by theangular velocity of the shaft 302 at that particular instant, but isdetermined by the length of time during which the angular velocity ofthe shaft 302 has been above that predetermined value, and by theparticular variations in angular velocity of shaft 302 which have takenplace since it first exceeded that predetermined value. The position ofthe slider along the resistance 318 is therefore determined by a timefunction of the velocity of shaft 302, integrated over the entireinterval during which value.

It has been found that, in an intake manifold pressure control system ofthe type described, the use of such a controller, which operates inaccordanc with an integrated function of the velocity of the compressor,provides a control which effectively limits the angular velocity of thecompressor without establishing a definite and absolute limit whichwould result in a hunting condition being set up. r

A limit control of the type described effectively prevents the limitingcondition from rising above a predetermined value, but neverthelessunder any given set 'of conditions,v permits a further increase in thelimiting condition, and thereby prevents sudden unbalancing effects inthe system which might cause undesirable hunting conditions to beestablished.

FIGURE 5 I have illustrated in Figure 5 a modification of the mechanicalconnections between th throttle motor, the throttle, and the manuallyoperable lever 55 of Figure 2, wherein a single electromagnet 400performs the functions of both the electromagnets 48 and 52 of Figure 2.Those elements in the structure of Figure 5 which are fully equivalentto the corresponding elements of Figure 2 have been given the samereference characters. Thpse elements will not be further described.

The electromagnet 400 in Figure 5 has a winding 4!." vand an armature402, which is pivotally attached to one arm of a bell-crank lever 403.The lever 403 is pivotally mounted on. a suitable support 404. The endof the arm of lever 403 .to'

which armature 402 is attached is slotted to. receive a pin carried onthe end of a thrust-rod 405. The thrust rod 405 carries the brake shoe41 at its inner end, and is adapted to slidably pass through an aperturein a suitable supporting-structure 406.

The other end of the bell-crank lever 403 terminates in an elongatedarcuate portion 401, which is .concentric with the shaft 42. A tensionspring 408 biases the lever 403 for rotation about its pivot in aclockwise direction, against the force exerted by the electromagnet 400.

The arm 53 carries a bracket 0 which projects between the arcuatesurface of the plate 4| and the arcuate portion 401 of bell-crank lever403. The bracket 0 is apertured to permit the passage of a pin 4. Thepin 4 is provided with a wide head at its upper end, the upper surfaceof which conforms to the lower surface of the arcuate portion 401 oflever 403. A compression spring 4l2 surrounds the pin 4l| bearing at itsupper end on the head of the pin 4 and 'at its lower end on the bracket0.

The lower end of the pin 4 is adapted to engage the notch 50 in theplate 4|. The compression spring 2 biases the pin 4 upwardly, so thatthe pin is normally free from the notch 50.

When the parts are in the position shown in the drawing, theelectromagnet 400 is energized, and the brake shoe 41 is thereby held inengagement with the ring gear 46. The link I9 through which the throttleis driven is then operably connected to the shaft 42. At the same time,the arcuate portion 401 of bell-crank lever 403 is held in the positionshown, wherein it is sufficiently spaced from the plate 4! so that thespring "2 maintains the pin 4 out of engagement with the notch 33'.

When the power to the electromagnet coil m is out ch. either by afailure of the source of ower or by the-opening of a switch such as thewitch 33 of Figure 2, the bell-crank lever 403 is moved clockwise fromthe position shown in the drawing by the biasing spring 408. The thrustrod 408 is therefore moved to the left, releasing the brake shoe 41 fromthe ring gear 48. Since the spring 408 is stronger than the compressionspring 412, the arcuate portion 401 of lever 403 moves downwardly,forcing the pin 4 downwardly and into engagement with the plate 4|. Asin the ease of the device shown in Figure 2, the pin 4 moves directlyinto the notch 50 if it happens to be aligned therewith. If it is notaligned therewith, the operator may move the arm 53 back and forth untilthe pin 4 becomes aligned with the notch 50, whereupon it will engagethat notch, and the operator may thereafter position the throttlemanually by operation of the manual control lever.

FIGURE 6 In Figure 6 I have illustrated a modification of my selectivemanual and automatic control mechanism wherein the throttle and themanual control lever automatically assume corresponding positions whenthe system is placed under manual control, so that the pilot or otheroperator does not have to fish for the throttle position, as in thesystems of Figures 2 and 5. Those elements in Figure 6 that correspondto equivalent elements in Figure 2 have been given the same referencecharacters.

The planet gears 43 of Figure 6 are carried by a spider 420. The spider420 also has an arm 42l, at the extremity of which the link is ispivotally connected. Another link 422v is also pivotally attached to theextremity of arm 421. The opposite end of link 422 carries a roller 423.

A pedestal 424, which may be mounted in the pilot's compartment of theaircraft, pivotally supports, as at 423, amanual control lever 423.

The upper end of lever 428 is. provided with a handle 421, by which thelever 428 may be rotated about its pivot 42!. The lower end of lever 428carries a slider 428 which. cooperates with a slidewireresistance 430.The slider 428 and the resistance430 of Figure 6 correspond to theslider 234 and resistance 23l of Figure 2. t

The manual control lever 426 is provided with a generally triangularaperture 43 l, within which the roller 423 is positioned. The lowervertex of the aperture 43I is provided with a narrow vertical portion,or notch, so that the link 422 is effectively pivotally attached to thelever 426 by the roller 423 when the latter rests in this narrowvertical portion.

A plate 432 is attached, as by pin and slot connection, to one surfaceof the pedestal 424. A tension spring 433 biases the plate 432 formovement in a downward direction from the position shown in the drawing.The plate 432 is maintained in the position shown by a latch plate 434,which is mounted, as by pin and slot connection, on the top of thepedestal 424 and which carries a hook 435 adapted to engage a flange onthe plate 432. v w

The latch plate 434 is also provided with handle 436, by means of whichthe'hook por- 'tion 435 may be moved to a position where it is outofengagement with the flange on the plate 432. when this occurs. the plate4321 ismoved downwardly by the spring 433, thereby carrying the link 422downwardly and moving the roller 423 into engagement with the narrowvertical portion of the aperture 43!. If the lever 420 happens to be ina different angular position from that shown in the drawing when theplate 432 is released, the roller 423 engages one of the sides of theaperture "I. The spring 433 is strong enough to act through the roller423 and cause rotation of lever 428 about its pivot 42!.

This rotation of lever 423 continues until the roller 423 rests in thelower vertex of the aperture 43!. It may be seen that at such a time,the handle42'l has been moved to a position corresponding to that of thethrottle l1. with the foregoing structure, if there should be a failureof electric power to the motor I03 and the electromagnet :8, or if suchpower has been intentionally interrupted by the pilot so that he cantake over manual control of the apparatus, the only other act necessaryby the pilot is for him to strike the handle 433 of the latch plate 434,whereupon the hook 435 disengages the plate 432. The plate 432 isthereupon moved downwardly by the spring 433 so that the roller 423 ofthe shaft 422 moves into the vertex of the aperture 43i in the plate423. If the plate 423 is relatively loose, then it is moved to aposition corresponding to the position of throttle valve 11 in themannerexplained above.

In some instances, friction members are applied to the shaft 423 andplate 423 so that the handle 421 tends to remain in any position inwhich it is placed, although it can be nevertheless manually moved bythe pilot. Under such conditions. upon release of plate 432 the spring433 cannot rotate the plate 423. The throttle l1, however, movesrelatively easily and, when such an arrangement is used, the throttle l1will move to a position corresponding to the position to which the pilothas adjusted the plate 423 by the handle 421. In this manner. the pilotmay place the manual control in a desired position before he places theapparatus under manual control. Then upon interrupting the circuits andstriking the handle 433, the throttle l1 will automatically move to thedesired position.

When power is restored to the electromagnet 48 and the motor I00, thepilot may restore the throttle to automatic control by manually liftingthe link 422 until the plate 432' is in a position where it may beengaged by the latch 43!.

" FIGURE 7 armature 442 against a stop 44!, in which position the plate440 is free from the latch I. When the electromagnet 443 is denergized,the armature 442 assumes that unlatched position, thereby releasing theplate 432, and placing the throttle under manual control. when power isrestored to the system, the armature 442 is again moved to the positionshown in the drawing against the tension of the spring 444. Thereafter,the plate 432 may be moved upwardly,

- l9 whereupon the flange 446 will pass over the surface of the latch Iand be engaged byits hookshaped upper surface.

nouns c There is illustrated in Figure 8 a modification of my selectiveautomatic or manual control mechanism, wherein the throttle isautomatically placed under the control of the manually operated leverwhen the 'power is turned off the system, and wherein the mechanism isautomatically reset upon the return of power so as to restore thethrottle to automatic control without the necessity of a manualresetting operation such as is required in the case of the arrangementdisclosed in Figures 6 and '1. In Figure 8, those elements which are thefull equivalent of the corresponding elements in Figure 2 have beengiven the same reference characters.

In Figure 8 there is shown a link 466, which may be operated by asuitable manual control lever in the same manner as the link 64 of F ure2 is operated by the manual control lever 66. The link 466 is pivotallyattached to a lever 46I. which is pivotally mounted at 462. The lowerend of lever 45I carries a slider 453 which cooperates with-a resistance464. The slider 463 and the resistance 464 correspond to the slider 234and the resistance 23I of Figure 2.

The upper portion of the lever 46I is provided with a. triangularaperture 466, of the same general shape as the aperture 43I in Figure 6.The upper vertex of the aperture 456 is provided with a narrow verticalportion, or notch, which is adapted to snugly receive a roller 456carried at the end of a link 451. The other end of the link 461 ispivotally attached to the end of the arm 42! which is driven by themotor I66 through the planetary gear train 43 during the automaticoperation of the throttle.

Another link 466 is pivotally attached to the link 451 at anintermediate point thereon. The opposite end of link 466 is pivotallyattached to the end of one arm of a bell-crank lever 46I, which ismounted for free rotation on a shaft 462. The opposite end of lever 46Iis connected by a tension spring 463 to a suitable support, so that thelever 46I is biased for rotation in a clockwise direction from theposition shown in the drawing.

The shaft 462 may be driven by a motor 464 acting through a gear train465.

The shaft 462 may be operably connected to the bell-crank lever 46Ithrough a planetary gear mechanism generally indicated at 466. Theplanetary gear mechanism 466 includes a sun gear 461 fixed on the shaft462, a plurality of planet gears 468 carried by the bell-crank lever46I, and an internal ring gear 466, which en-- circles the planet gears468 and is suitably supported so as to be maintained enmeshed with theplanet gears 468, and at the same time to permit freedom of rotation ofthe ring gear 466 about the shaft 462.

A brake shoe 416 is provided for operative engagement with the externalsurface of the ring gear 466 so as to lock that gear against rotation.

The brake shoe 416 associated with the ring gear 466 of the planetarygear mechanism 466 and the brake shoe 41 associated with the ring gear46 of the planetary gear mechanism 43 are both carried by a togglelinkage arrangement generally indicated at "I. This toggle linkageincludes a link 412 attached to the armature 413 of an electromagnet414. The armature 413 is ment with their respective ring gears, thereby-20' biased by a spring 416 to a position wherein the toggle linkage 41lreleases both the brake shoe 41 and 416 from the surfaces of theircooperating ring gears. Upon energization of coil 416 of electromagnet414, the armature 413 is moved downwardly to the position shown in thedrawing, and the toggle linkage 4" is operated to force both the brakeshoes 416 and 41 into engagelocking those gears against rotation.

The motor 464 is connected by conductors 466 and 48| .to power supplylines 482 and 483, respectively. A switch 464 and a fuse 486 areconnected in series with the line 462. The winding 416 of electromagnet414 is connected to lines 462 and 463 by conductors 466 and 481respectively. The supply lines 462 and 483 are also connected to thethrottle amplifier I I I and the waste gate amplifier 2 II to supplypower to the amplifier.

Operation of Figure 8 When the parts are in the positions shown in thedrawing, the position of the throttle I1 is controlled by the motor I66.The electromagnet 414 is energized, thereby maintaining the brake shoe41 in engagement with the ring gear 46, and completing the drivingconnection between the motor I66 and the throttle I1. The brake shoe 416likewise engages the ring gear 466, completing the driving connectionbetween the motor 464 and the bell-crank lever 46I. The bell-crank leverI has reached its limit of motion in a counterclockwise direction, sinceit engages the stop 462. Therefore, the motor 464 is stalled. Manualoperation of the lever 46I through the link 456 at this time causes thepositioning of slider 453 relative to resistance 454, and does notdirectly affect the position of the throttle I1.

Now let it be assumed that the system is deenergized, which may resulteither from failure of the power supply, or from opening of the switch484. Deenergization of electromagnet 414 causes both the brake shoes 41and 416 to release their respective ring gears. Therefore, the drivingconnection between motor I66 and throttle I1 is interrupted, since thearm 42I may now rotate freely, regardless of the position of the sungear 44 which is driven by motor I66. Similarly, the release of the ringgear 466 by the brake shoe 416 allows the bell-crank lever 46I to turnin a clockwise direction under the influence of the biasing spring 463.As the bell-crank lever 46I turns clockwise, the link 461 is movedupwardly, and the roller 456 moves upwardly until it engages the innersurface of the aperture 455. When the roller 456 engages the innersurface of aperture 455, the lever 45| is driven thereby into a positioncorresponding to that of throttle I1.

If the link 466 is locked at this time, the engagement of roller 466with the inner surface of the aperture 456 results in a positioning ofthe throttle I1 so that its position corresponds with that of the manuallever which controls the link 456.

Upon restoration of power to the system, the electromagnet 414 is againenergized, thereby moving the brake shoe 41 into engagement with thering gear 46. This places the throttle I1 under control of motor I66. Atthe same time, the brake shoe 416 is operated to lock the ring gear 466,thereby completing the driving connection between the motor 464 and thebell-crank lever 46I. The connections of the motor 464 are such that itis energized for operation in a direction to drive the bell-crank leverI in a counterclockwise direction against the tension of spring 463.Rotation of the bell-crank lever "I in a counterclockwise directioncauses the roller I. to move downwardly into the wide portion of theaperture 455, thereby releasing the mechanical connection between thelink 450 and the throttle IT. The bell-crank lever 6| continues torotate counterclockwise until it engages stop 49!, whereupon motor 464is stalled.

It may therefore be seen that in the arrangement of Figure 8, thethrottle I1 is positioned by the motor Hill as long as power is suppliedto the system, but when the supply of power to the system isdiscontinued, the throttle lever," is mechanically connected to themanually operated link 450, and when power is returned to the system,the mechanical connection between throttle I! and link 450 isinterrupted and the throttle I1 is again placed under control of themotor III without the necessity of any manual resetting operation.

While I have shown and described certain preferred embodiments of myinvention, other modifications thereof will occur to those skilled inthe art, and I therefore wish my invention to be limited only by theappended claims.

I claim as my invention:

1. Control apparatus, comprising in combination, a load device to bepositioned, electrical motor means for positioning said load device, amanually operable control member, a first pivotally mounted memberattached to said load device for simultaneous movement therewith, asecond member pivotally mounted concentric with said first member andmanually movable, an electromagnet mounted on one of said pivotallymounted members, said electromagnet comprising an electrical winding, anarmature movable toward said windin upon energization thereof, andspring means biasing said armature away from said winding, the other ofsaid pivotally mounted members having an arcuate surface concentric withsaid pivotal mounting and notched to receive said armature upon movementthereof away from said winding, said armature serving upon engagementwith said notch as a mechanical connection between said members, andmeans connecting said winding and said motor means to the same source ofelectrical energy.

2. Control apparatus, comprisin in combination, a load device to bepositioned, electrical motor means for driving said load device, aplanetary gear train between said -motor means and said load deviceincluding one gear which when said gear is held stationary operativelyconnects the motor means to the load device and when said gear isreleased operatively disconnects the motor means from the load device, amanually operable control member, a first element connected to saidmanually operable control member, a second element connected to saidload device, means biasing said elements into engagement with eachother, said elements having inter-engagin parts of such nature that theycan be engaged together in only one relative position to each other, andmeans including at least one electromagnet and operative when saidelectromagnet is energized to hold said gear and to hold said elementsdisengaged against the action of said biasing means, and operative whensaid electromagnet is deenergized to release said gear and to allow saidelements to move out at 22 their disengaged position under the influenceof said biasing means.

3. Control apparatus, comprising in combination, a load device to bepositioned, electrical motor means for positioning said load device, a

manually operable control member, an element movable between a firstposition wherein it mechanically connects said member and said loaddevice and a second position wherein said member is mechanicallydisconnected from said load device, means biasing said element to saidfirst position, means including an electromagnet and operative when saidelectromagnet is energized to hold said element in said second positionagainst the action of said biasing means, motive power means, meansoperable to connect said motive power means to said element to drivesaid element to said second position, said connecting means comprising aplanetary gear train, means connecting said motive power means to onegear of said train, means operable to hold, another gear of said trainagainst rotation, and means operable to connect a third gear of saidtrain to said element.

4. Control apparatus, comprising in combination, a load device to bepositioned, electrical motor means for driving said load device, a firstgear train between said motor means and said load device including onegear which when said gear is held stationary operatively connects themotor means to the load device and when said gear is releasedoperatively disconnects the motor means from the load device,electromagnetic means eifective when energized to hold said one gear toconnect said motor means to said load device and when deenergized torelease said one gear, a manually operable control member, an

' element movable between a first position where-. in it mechanicallyconnects said member and said load device and a second position whereinsaid member is mechanically disconnected from said load device, meansbiasin said element to said first position, additional electrical motormeans for driving said element to said second position, a second geartrain between said additional motor means and said element includin onegear which when said gear is held stationary operatively con nects themotor means to the element to drive said element to said second positionand to retain it in that position and when said gear is releasedoperatively disconnects the motor means from the element, andelectromagnetic means effective when energized to hold the said onegears of both said gear trains and when deenergized to release said onegears.

5. Control apparatus, comprisin in combination, a load device to bepositioned, electric motor means arranged for connection to drive saidload device, electric circuit means connected to said motor to controlthe operation thereof, said circuit means comprising a variableresistance device responsive to a pressure condition and a secondvariable resistance device electrically connected to said first namedresistance device for adjusting the value of said pressure condition atwhich said load device is maintained in a predetermined position by saidmotor means, a manually movable member connected to adjust said secondvariable resistance device, and means for disconnecting said motor meansfrom said load device and for connecting said load device to saidmanually movable member for operation thereby.

6. Electrical control apparatus, comprising in combination, a loaddevice to be positioned, elec- 23 trlcal motor means for driving saidload device, electrical circuit means including means for varying anelectrical quantity therein in accordance with a condition indicative ofthe need for operation of said load device, means responsive to adeviation in the value of said quantity from a predetermined value forcontrolling said motor means, means driven by said motor means forrestoring said electrical quantity to said predetermined value,electrical means for adjusting the value of said condition at which saidload device is maintained in a predetermined position by said motormeans, a manually movable memher for controllin said electricaladjusting means, means operable to releasably connect said member andsaid load device, and electrical means operative when energized toconnect said motor means and said load device and to maintain saidmember disconnected from said load device and when deenergized to permitconnection of said member and said load device and to operativelydisconnect said motor means from said load device.

7. Apparatus for controlling the position of the throttle of an internalcombustion engine, comprising in combination, motor means for drivingsaid throttle, means for controlling said motor means including a deviceresponsive to a condition indicative of the need for operation of saidthrottle, electrical means for adjusting the value of said condition atwhich said throttle is maintained in a predetermined position by saidmotor means, a manually movable member for operating said electricaladjusting means, and means for disconnecting said motor means from saidthrottle and for connectin said throttle to said manually movable memberfor operation thereby.

8. Apparatus for controlling the pressure in the intake manifold of aninternal combustion engine provided with a throttle for regulating thesupply of air to said manifold, comprising in combination, motor meansfor driving said throttle, means for controlling said motor meansincluding a variable impedance device responsive to the pressure in saidintake manifold, variable impedance means for adjusting the pressurevalue at which said throttle is maintained in a predetermined positionby said motor means, a manually movable member for operating saidadjusting means, and means for disconnecting said motor means from saidthrottle and for connectin said throttle to said manually movablecontrol member for operation thereby.

9. Apparatus for controlling the pressure in the intake manifold of aninternal combustion engine provided with a throttle for regulating thesupply of air to said manifold, and a compressor driven by a turbinepowered with exhaust gases from said engine, comprisin in combination,first motor means for driving said throttle, means for controlling thecompression ratio of said compressor, second motor means for drivin saidcompression ratio controlling means, means for controlling said firstand second motor means including a device responsive to the pressure insaid intake manifold, said controlling means being responsive to anoperation of said device indicative of a decrease in said pressure firstto control said first motor means to open said throttle and thereafterto control said second motor means to increase said compression ratio,means for adjusting the pressure value at which said throttle andcompression ratio controlling means are maintained in predeterminedpositions, a manually movable member for operating resistance, deviceresponsive to the pressure in said intake manifold, variable resistancemeans for adjusting the pressure value at which said throttle ismaintained in a predetermined position by said motor means, a manuallymovable member for operating said adjusting means, means operable toreleasably connect said member and said throttle, electrical meansoperative when energized to connect said motor means and said throttleand to maintain said member disconnected from said throttle and whendeenergized to permit connection of said member and said throttle and tooperatlvely disconnect said motor means from said throttle, a source ofelectrical energy. and means connecting both said electrical means andsaid motor means to said source.

11. In combination, an engine fuel control means, a lever for movingsaid fuel control means to control the manifold pressure, automaticcontrol means to disconnect said lever from said fuel control means andthereafter, responsive to variation in manifold pressure, to move saidfuel control means to maintain a substantially constant manifoldpressure, and variable impedance means responsive to the position ofsaid lever to calibrate said automatic control means to maintain apredetermined pressure.

12. In combination, an engine fuel control means, a lever for movingsaid fuel control means to establish a manifold pressure, automaticelectrical means, including means to disconnect said lever from saidfuel control means, responsive to variations in manifold pressure, tomove said fuel control means to maintain substantially constant, themanifold pressure established b said lever, and electrical means toestablish a new manifold pressure which will be thereafter maintainedconstant by the automatic control means, without re-establishing themanual control.

13. A throttle control system for regulating manifold pressurescomprising, in combination, a manual means and an electric means foradlusting the throttle, a single solenoid, a clutch apparatus controlledby the solenoid comprising mechanical means movable in one directionwhen the solenoid is energized to connect the electric means to thethrottle and in the opposite direction when the solenoid is deenergizedto disconnect the motor and connect the manual means to the throttle,and means included in said apparatus effective when the manual means isconnected to the throttle to cause the manual means to indicatephysically the position of the throttle.

14. A throttle control system comprising, in combination, manual andelectric means for moving said throttle to provide a desired manifoldpressure, a single clutch apparatus movable to interconnect either saidmanual moving means or said electric moving means with said throttle.said clutch apparatus being so constructed as to be effective upondisconnection of said electrical means and connection with said throttlefor caus- ALBERT E. BAAK.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date Ongley June 2, 1896 TitterlnztonOct. 30, 1923 Number 26 Name Date Dean May 5, 1925 De Giorgi Nov. 17,1931 Jones June 28, 1932 Kronmiller June 8, 1937 Hodgson July 6, 1937Trott June 20, 1944 Truesdell Sept. 19, 1944 Fawkes Oct. 16, 1945 WilsonMar. 19, 1946 Andrews et a1 Mar. 30, 1948

